Touch detection at bezel edge

ABSTRACT

This relates to a method of extrapolating proximity information to generate a border column or row of touch nodes (also known as touch pixels) and then fitting an ellipse to the contact patch including the extrapolated border touch nodes. Additionally, a contact can be identified as a thumb based on both its major axis and its distance to an edge of the touch sensing surface.

FIELD OF THE DISCLOSURE

This relates generally to electronic devices with touch sensingcapabilities.

BACKGROUND OF THE DISCLOSURE

In a touch sensing system, a proximity image may be obtained from atouch sensing surface, and the image may be segmented into a pluralityof patches, each corresponding to a contact on or near the touch sensingsurface. An ellipse may be fit to each of the plurality of patches. Theparameters of the ellipse may be used to identify the contact patchesand generate input. However, when a contact patch is on the edge of aproximity image, a fitted ellipse may not accurately represent thesensed touch object, some of which may be past the edge of the touchsensing surface.

SUMMARY OF THE DISCLOSURE

This relates to a method of extrapolating proximity information togenerate a border column or row of touch nodes (also known as touchpixels) and then fitting an ellipse to the contact patch including theextrapolated border touch nodes. Additionally, a contact can beidentified as a thumb based on both its major axis and its distance toan edge of the touch sensing surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate exemplary proximity images includingextrapolated border nodes according to examples of the disclosure.

FIG. 2 illustrates an exemplary method of extrapolating border nodes forfitting an ellipse according to examples of the disclosure.

FIG. 3 illustrates a graph of major axis of a contact versus distancefrom an edge of a touch sensing surface according to examples of thedisclosure.

FIG. 4 illustrates an exemplary method of identifying a contact as athumb according to examples of the disclosure.

FIG. 5 is a block diagram illustrating an exemplary API architecture,which may be used in some examples of the disclosure.

FIG. 6 illustrates an exemplary software stack of an API according toexamples of the disclosure.

FIG. 7 is a block diagram illustrating exemplary interactions betweenthe touch screen and the other components of the device according toexamples of the disclosure.

FIG. 8 is a block diagram illustrating an example of a systemarchitecture that may be embodied within any portable or non-portabledevice according to examples of the disclosure.

DETAILED DESCRIPTION

In the following description of examples, reference is made to theaccompanying drawings which form a part hereof, and in which it is shownby way of illustration specific examples that can be practiced. It is tobe understood that other examples can be used and structural changes canbe made without departing from the scope of the disclosed examples.

Although examples disclosed herein may be described and illustratedherein primarily in terms of capacitive touch sensing and proximitysensing, it should be understood that the examples are not so limited,but are additionally applicable to other touch sensing technologies,including those that sense only force and/or use resistive touchsensing. For example, a “proximity image” as discussed herein may be animage of capacitance, an image of resistance, and/or an image of force,among other possibilities. Additionally, although examples are primarilydiscussed in terms of columns, the methods disclosed herein can be alsoused in terms of rows.

In a touch sensing system, a proximity image may be obtained from atouch sensing surface, and the image may be segmented into a pluralityof patches, each corresponding to a contact on or near the touch sensingsurface. An ellipse may be fit to each of the plurality of patches. Theparameters of the ellipse may be used to identify the contact patchesand generate input. For example, a contact patch may be identified as athumb based on a length of a major axis of the fitted ellipse. However,when a contact patch is on the edge of a proximity image, a fittedellipse may not accurately represent the sensed touch object, some ofwhich may be past the edge of the touch sensing surface.

FIGS. 1A and 1B illustrate a method of extrapolating proximityinformation to generate a border column or row of touch nodes (alsoknown as touch pixels) and then fitting an ellipse to the contact patchincluding the extrapolated border touch nodes.

In FIG. 1A, an outline of a thumb is shown and the touch nodes of thecontact patch corresponding to the thumb are shown in edge column C1 andadjacent column C2. The centroids y1 and y2 of columns C1 and C2,respectively, can be calculated and extrapolated to determine y0, anextrapolated centroid for a border column C0. The touch nodes in columnC1 of the thumb patch can be copied into column C0 and shifted so thatthe centroid is at y0. Additionally, the sums Sum1 and Sum 2 of thetouch nodes in columns C1 and C2, respectively, of the thumb patch canbe calculated and extrapolated to determine Sum0 and the touch nodescopied to column C0 can be appropriately scaled based on theextrapolated Sum0. In some examples, the touch nodes in column C0 can befurther scaled down (in this case ⅓) to discount for uncertainty in theextrapolation.

In FIG. 1B, the algorithm is illustrated and described in terms of aproximity image of capacitance. That is, each touch node is acapacitance value that represents proximity of a contact to that touchnode. FIG. 1B also illustrates at (1) how a fingerprint that overlapsthe edge of a touch sensing surface can create a misleading proximityimage. At (2 a)-(4) the outline of the actual fingerprint is shown as adotted line. After extrapolating border pixels, the solid-line ellipseestimated at (4) more accurately represents the actual fingerprint shownat (1).

FIG. 1B also illustrates a trivial ellipse 100 estimated from theinitial touch nodes without extrapolation, an extrapolated ellipse 102estimated from the touch nodes including the additional border nodesadded through extrapolation, and the actual fingerprint outline 104. Thetrivial ellipse 100 has a shorter major axis and a longer minor axis,and its orientation points closer to the top of the proximity image thanthe ellipse of the actual fingerprint outline 104. By contrast, theextrapolated ellipse 102 has a longer major axis than the trivialellipse 100, and its orientation is much closer to the orientation ofthe actual fingerprint outline 104. As can be seen, including theextrapolated border nodes allows for an estimated ellipse withparameters more accurate to the sensed touch object.

FIG. 2 illustrates an exemplary method of extrapolating border nodes forfitting an ellipse according to examples of the disclosure. A proximityimage may be obtained and segmented into a plurality of patches (200). Afirst patch of the plurality may include one or more touch nodes in anedge column of the proximity image. Additionally, the first patch mayinclude one or more touch nodes in a column adjacent to the edge column.

An edge column centroid of the one or more touch nodes of the firstpatch in the edge column may be determined (202). A centroid calculationis similar to a center of mass calculation. For example, a centroid canbe calculated as a weighted average of the positions of the one or moretouch nodes, each position being weighted by the relative proximityvalue of the touch node at that position. An adjacent column centroid ofthe one or more touch nodes of the first patch in the adjacent columnmay be determined in a similar manner (204).

The one or more touch nodes of the first patch in the edge column may becopied into a border column and offset by an extrapolation of the edgecolumn centroid and the adjacent column centroid (206). In someexamples, the centroids may be extrapolated by subtracting the adjacentcolumn centroid from the edge column centroid to obtain a shift value.The touch nodes copied into the border column may then be shifted basedon the shift value. In some examples, the shift value may be an integeror may be rounded to an integer so that each of the touch nodes may betrivially shifted based on the shift value.

In some examples, the shift value may not be an integer and shifting thecopied touch nodes in the border column includes interpolating the touchnodes based on the shift value. For example, if the shift value is 0.6,then for each touch node 60% of the proximity value of the touch nodemay be shifted up to the next touch node and 40% of the proximity valuemay remain in the touch node. The remaining 40% may be added to the 60%of the below touch node that is shifted up. In some examples, othermethods of interpolating the touch nodes based on a non-integer shiftvalue may be used.

The one or more touch nodes of the first patch in the edge column may besummed to obtain an edge sum. This can include summing the proximityvalues of the one or more touch nodes. In a similar fashion, the one ormore touch nodes of the first patch in the adjacent column may be summedto obtain an adjacent sum. The touch nodes in the border column may thenbe scaled based on an extrapolation of the edge sum and the adjacent sum(208). The touch nodes in the border column may be scaled such that thesum of the proximity values of the touch nodes in the border column isequal to the extrapolation of the edge sum and the adjacent sum. In someexamples, the extrapolation may be a linear extrapolation of thetrajectory of the adjacent sum to the edge sum. In other examples, theextrapolation may be a logistic extrapolation of the trajectory of theadjacent sum to the edge sum, such as an extrapolation based on asigmoid function.

An ellipse may be fit to the first patch including the touch nodes ofthe border column (210). In some examples, fitting an ellipse mayinclude determining parameters of the ellipse, such as a major axis, aminor axis, and an angle of orientation of the ellipse.

As discussed above, a contact may be identified as a thumb based on thelength of the major axis of an ellipse fit to the contact. However, acontact that overlaps the edge of the touch sensing surface may have ashorter major axis and thus it may not be able to be identified as athumb until most of the contact moves onto the touch sensing surface.

FIG. 3 illustrates a graph of a major axis of a contact versus distancefrom an edge of a touch sensing surface. When a contact is right on theedge of the touch sensing surface, the major axis of the contact is veryshort, but as the contact moves from the edge and more of the contacttouches the surface, the length of the major axis increases until itstabilizes to the actual length of the major axis of the full contact.The dotted line 300 represents a possible threshold major axis lengthabove which the contact may be identified as a thumb. The curve 302represents the relationship between major axis and distance from theedge for a generic finger contact. The curve 306 represents therelationship between major axis and distance from the edge for a thumbcontact.

The curve 304 represents a reference thumb profile that can be used toidentify a contact as a thumb. The major axis and the distance from theedge can be monitored for a contact over a series of time steps, and thearea between the curve for a contact and the reference thumb profile 304can be integrated and accumulated. If the integrated value remainspositive, as it would with curve 306, then the associated contact can beidentified as a thumb. If the integrated value becomes negative, as itwould with curve 302, then it can be determined that the associatedcontact is not a thumb. This method can be fairly robust, because evenif a non-thumb contact has an unusually large major axis when it isclose to the edge, as it moves away from the edge the major axis willgrow slowly and enough negative area will accumulate such that thecontact will not be identified as a thumb. In some examples, theintegrated value may be accumulated and the contact may not beidentified until a time threshold is exceeded or a distance thresholdfrom the edge is exceeded, among other possibilities.

FIG. 4 illustrates an exemplary method of identifying a contact as athumb based on the major axis of the contact and the contact's distancefrom the edge of the touch sensing surface. A major axis of a contactand a distance of the contact from the edge of the touch sensing surfacemay be obtained (400).

Based on a thumb profile, a reference major axis of a thumb contact maybe determined at the obtained distance (402). A thumb profile may simplybe a mapping of distances to major axis values, as illustrated in FIG.3. Determining the reference major axis can include obtaining thereference major axis from the thumb profile based on the obtaineddistance of the contact from the edge of the touch sensing surface.

The contact may be identified as a thumb based on the reference majoraxis and the major axis of the contact (404). For example, the referencemajor axis and the major axis of the contact may be used to integratethe area between a curve for the contact and a curve for the thumbprofile, as described with reference to FIG. 3. If the integrated valueis positive, the contact may be identified as a thumb.

In some examples, the reference major axis may be subtracted from themajor axis of the contact to obtain an axis difference. In one example,the contact may be identified as a thumb if the axis difference ispositive. In other examples, the axis difference may be added to a sumof axis differences from previous time steps. The contact may beidentified as a thumb if the sum of axis differences is positive.

The examples discussed above can be implemented in one or moreApplication Programming Interfaces (APIs). An API is an interfaceimplemented by a program code component or hardware component(hereinafter “API-implementing component”) that allows a differentprogram code component or hardware component (hereinafter “API-callingcomponent”) to access and use one or more functions, methods,procedures, data structures, classes, and/or other services provided bythe API-implementing component. An API can define one or more parametersthat are passed between the API-calling component and theAPI-implementing component.

The above-described features can be implemented as part of anapplication program interface (API) that can allow it to be incorporatedinto different applications (e.g., spreadsheet apps) utilizing touchinput as an input mechanism. An API can allow a developer of anAPI-calling component (which may be a third party developer) to leveragespecified features, such as those described above, provided by anAPI-implementing component. There may be one API-calling component orthere may be more than one such component. An API can be a source codeinterface that a computer system or program library provides in order tosupport requests for services from an application. An operating system(OS) can have multiple APIs to allow applications running on the OS tocall one or more of those APIs, and a service (such as a programlibrary) can have multiple APIs to allow an application that uses theservice to call one or more of those APIs. An API can be specified interms of a programming language that can be interpreted or compiled whenan application is built.

In some examples, the API-implementing component may provide more thanone API, each providing a different view of the functionalityimplemented by the API-implementing component, or with different aspectsthat access different aspects of the functionality implemented by theAPI-implementing component. For example, one API of an API-implementingcomponent can provide a first set of functions and can be exposed tothird party developers, and another API of the API-implementingcomponent can be hidden (not exposed) and provide a subset of the firstset of functions and also provide another set of functions, such astesting or debugging functions which are not in the first set offunctions. In other examples the API-implementing component may itselfcall one or more other components via an underlying API and thus be bothan API-calling component and an API-implementing component.

An API defines the language and parameters that API-calling componentsuse when accessing and using specified features of the API-implementingcomponent. For example, an API-calling component accesses the specifiedfeatures of the API-implementing component through one or more API callsor invocations (embodied for example by function or method calls)exposed by the API and passes data and control information usingparameters via the API calls or invocations. The API-implementingcomponent may return a value through the API in response to an API callfrom an API-calling component. While the API defines the syntax andresult of an API call (e.g., how to invoke the API call and what the APIcall does), the API may not reveal how the API call accomplishes thefunction specified by the API call. Various API calls are transferredvia the one or more application programming interfaces between thecalling (API-calling component) and an API-implementing component.Transferring the API calls may include issuing, initiating, invoking,calling, receiving, returning, or responding to the function calls ormessages; in other words, transferring can describe actions by either ofthe API-calling component or the API-implementing component. Thefunction calls or other invocations of the API may send or receive oneor more parameters through a parameter list or other structure. Aparameter can be a constant, key, data structure, object, object class,variable, data type, pointer, array, list or a pointer to a function ormethod or another way to reference a data or other item to be passed viathe API.

Furthermore, data types or classes may be provided by the API andimplemented by the API-implementing component. Thus, the API-callingcomponent may declare variables, use pointers to, use or instantiateconstant values of such types or classes by using definitions providedin the API.

Generally, an API can be used to access a service or data provided bythe API-implementing component or to initiate performance of anoperation or computation provided by the API-implementing component. Byway of example, the API-implementing component and the API-callingcomponent may each be any one of an operating system, a library, adevice driver, an API, an application program, or other module (itshould be understood that the API-implementing component and theAPI-calling component may be the same or different type of module fromeach other). API-implementing components may in some cases be embodiedat least in part in firmware, microcode, or other hardware logic. Insome examples, an API may allow a client program to use the servicesprovided by a Software Development Kit (SDK) library. In other examplesan application or other client program may use an API provided by anApplication Framework. In these examples the application or clientprogram may incorporate calls to functions or methods provided by theSDK and provided by the API or use data types or objects defined in theSDK and provided by the API. An Application Framework may in theseexamples provide a main event loop for a program that responds tovarious events defined by the Framework. The API allows the applicationto specify the events and the responses to the events using theApplication Framework. In some implementations, an API call can reportto an application the capabilities or state of a hardware device,including those related to aspects such as input capabilities and state,output capabilities and state, processing capability, power state,storage capacity and state, communications capability, etc., and the APImay be implemented in part by firmware, microcode, or other low levellogic that executes in part on the hardware component.

The API-calling component may be a local component (i.e., on the samedata processing system as the API-implementing component) or a remotecomponent (i.e., on a different data processing system from theAPI-implementing component) that communicates with the API-implementingcomponent through the API over a network. It should be understood thatan API-implementing component may also act as an API-calling component(i.e., it may make API calls to an API exposed by a differentAPI-implementing component) and an API-calling component may also act asan API-implementing component by implementing an API that is exposed toa different API-calling component.

The API may allow multiple API-calling components written in differentprogramming languages to communicate with the API-implementing component(thus the API may include features for translating calls and returnsbetween the API-implementing component and the API-calling component);however the API may be implemented in terms of a specific programminglanguage. An API-calling component can, in one example, call APIs fromdifferent providers such as a set of APIs from an OS provider andanother set of APIs from a plug-in provider and another set of APIs fromanother provider (e.g. the provider of a software library) or creator ofthe another set of APIs.

FIG. 5 is a block diagram illustrating an exemplary API architecture,which may be used in some examples of the disclosure. As shown in FIG.5, the API architecture 500 includes the API-implementing component 510(e.g., an operating system, a library, a device driver, an API, anapplication program, software or other module) that implements the API520. The API 520 specifies one or more functions, methods, classes,objects, protocols, data structures, formats and/or other features ofthe API-implementing component that may be used by the API-callingcomponent 530. The API 520 can specify at least one calling conventionthat specifies how a function in the API-implementing component receivesparameters from the API-calling component and how the function returns aresult to the API-calling component. The API-calling component 530(e.g., an operating system, a library, a device driver, an API, anapplication program, software or other module), makes API calls throughthe API 520 to access and use the features of the API-implementingcomponent 510 that are specified by the API 520. The API-implementingcomponent 510 may return a value through the API 520 to the API-callingcomponent 530 in response to an API call.

It will be appreciated that the API-implementing component 510 mayinclude additional functions, methods, classes, data structures, and/orother features that are not specified through the API 520 and are notavailable to the API-calling component 530. It should be understood thatthe API-calling component 530 may be on the same system as theAPI-implementing component 510 or may be located remotely and accessesthe API-implementing component 510 using the API 520 over a network.While FIG. 5 illustrates a single API-calling component 530 interactingwith the API 520, it should be understood that other API-callingcomponents, which may be written in different languages (or the samelanguage) than the API-calling component 530, may use the API 520.

The API-implementing component 510, the API 520, and the API-callingcomponent 530 may be stored in a non-transitory machine-readable storagemedium, which includes any mechanism for storing information in a formreadable by a machine (e.g., a computer or other data processingsystem). For example, a machine-readable medium includes magnetic disks,optical disks, random access memory; read only memory, flash memorydevices, etc.

In the exemplary software stack shown in FIG. 6, applications can makecalls to Services A or B using several Service APIs and to OperatingSystem (OS) using several OS APIs. Services A and B can make calls to OSusing several OS APIs.

Note that the Service 2 has two APIs, one of which (Service 2 API 1)receives calls from and returns values to Application 1 and the other(Service 2 API 2) receives calls from and returns values to Application2. Service 1 (which can be, for example, a software library) makes callsto and receives returned values from OS API 1, and Service 2 (which canbe, for example, a software library) makes calls to and receivesreturned values from both OS API 1 and OS API 2. Application 2 makescalls to and receives returned values from OS API 2.

FIG. 7 is a block diagram illustrating exemplary interactions betweenthe touch screen and the other components of the device. Describedexamples may include touch I/O device 1001 that can receive touch inputfor interacting with computing system 1003 via wired or wirelesscommunication channel 1002. Touch I/O device 1001 may be used to provideuser input to computing system 1003 in lieu of or in combination withother input devices such as a keyboard, mouse, etc. One or more touchI/O devices 1001 may be used for providing user input to computingsystem 1003. Touch I/O device 1001 may be an integral part of computingsystem 1003 (e.g., touch screen on a smartphone or a tablet PC) or maybe separate from computing system 1003.

Touch I/O device 1001 may include a touch sensing panel which is whollyor partially transparent, semitransparent, non-transparent, opaque orany combination thereof. Touch I/O device 1001 may be embodied as atouch screen, touch pad, a touch screen functioning as a touch pad(e.g., a touch screen replacing the touchpad of a laptop), a touchscreen or touchpad combined or incorporated with any other input device(e.g., a touch screen or touchpad disposed on a keyboard) or anymulti-dimensional object having a touch sensing surface for receivingtouch input.

In one example, touch I/O device 1001 embodied as a touch screen mayinclude a transparent and/or semitransparent touch sensing panelpartially or wholly positioned over at least a portion of a display.According to this example, touch I/O device 1001 functions to displaygraphical data transmitted from computing system 1003 (and/or anothersource) and also functions to receive user input. In other examples,touch I/O device 1001 may be embodied as an integrated touch screenwhere touch sensing components/devices are integral with displaycomponents/devices. In still other examples a touch screen may be usedas a supplemental or additional display screen for displayingsupplemental or the same graphical data as a primary display and toreceive touch input.

Touch I/O device 1001 may be configured to detect the location of one ormore touches or near touches on device 1001 based on capacitive,resistive, optical, acoustic, inductive, mechanical, chemicalmeasurements, or any phenomena that can be measured with respect to theoccurrences of the one or more touches or near touches in proximity todevice 1001. Software, hardware, firmware or any combination thereof maybe used to process the measurements of the detected touches to identifyand track one or more gestures. A gesture may correspond to stationaryor non-stationary, single or multiple, touches or near touches on touchI/O device 1001. A gesture may be performed by moving one or morefingers or other objects in a particular manner on touch I/O device 1001such as tapping, pressing, rocking, scrubbing, twisting, changingorientation, pressing with varying pressure and the like at essentiallythe same time, contiguously, or consecutively. A gesture may becharacterized by, but is not limited to a pinching, sliding, swiping,rotating, flexing, dragging, or tapping motion between or with any otherfinger or fingers. A single gesture may be performed with one or morehands, by one or more users, or any combination thereof.

Computing system 1003 may drive a display with graphical data to displaya graphical user interface (GUI). The GUI may be configured to receivetouch input via touch I/O device 1001. Embodied as a touch screen, touchI/O device 1001 may display the GUI. Alternatively, the GUI may bedisplayed on a display separate from touch I/O device 1001. The GUI mayinclude graphical elements displayed at particular locations within theinterface. Graphical elements may include but are not limited to avariety of displayed virtual input devices including virtual scrollwheels, a virtual keyboard, virtual knobs, virtual buttons, any virtualUI, and the like. A user may perform gestures at one or more particularlocations on touch I/O device 1001 which may be associated with thegraphical elements of the GUI. In other examples, the user may performgestures at one or more locations that are independent of the locationsof graphical elements of the GUI. Gestures performed on touch I/O device1001 may directly or indirectly manipulate, control, modify, move,actuate, initiate or generally affect graphical elements such ascursors, icons, media files, lists, text, all or portions of images, orthe like within the GUI. For instance, in the case of a touch screen, auser may directly interact with a graphical element by performing agesture over the graphical element on the touch screen. Alternatively, atouch pad generally provides indirect interaction. Gestures may alsoaffect non-displayed GUI elements (e.g., causing user interfaces toappear) or may affect other actions within computing system 1003 (e.g.,affect a state or mode of a GUI, application, or operating system).Gestures may or may not be performed on touch I/O device 1001 inconjunction with a displayed cursor. For instance, in the case in whichgestures are performed on a touchpad, a cursor (or pointer) may bedisplayed on a display screen or touch screen and the cursor may becontrolled via touch input on the touchpad to interact with graphicalobjects on the display screen. In other examples in which gestures areperformed directly on a touch screen, a user may interact directly withobjects on the touch screen, with or without a cursor or pointer beingdisplayed on the touch screen.

Feedback may be provided to the user via communication channel 1002 inresponse to or based on the touch or near touches on touch I/O device1001. Feedback may be transmitted optically, mechanically, electrically,olfactory, acoustically, or the like or any combination thereof and in avariable or non-variable manner.

Attention is now directed towards examples of a system architecture thatmay be embodied within any portable or non-portable device including butnot limited to a communication device (e.g. mobile phone, smart phone),a multi-media device (e.g., MP3 player, TV, radio), a portable orhandheld computer (e.g., tablet, netbook, laptop), a desktop computer,an All-In-One desktop, a peripheral device, or any other system ordevice adaptable to the inclusion of system architecture 2000, includingcombinations of two or more of these types of devices. FIG. 8 is a blockdiagram of one example of system 2000 that generally includes one ormore computer-readable mediums 2001, processing system 2004, I/Osubsystem 2006, radio frequency (RF) circuitry 2008, audio circuitry2010, and gaze detection circuitry 2011. These components may be coupledby one or more communication buses or signal lines 2003.

It should be apparent that the architecture shown in FIG. 8 is only oneexample architecture of system 2000, and that system 2000 could havemore or fewer components than shown, or a different configuration ofcomponents. The various components shown in FIG. 8 can be implemented inhardware, software, firmware or any combination thereof, including oneor more signal processing and/or application specific integratedcircuits.

RF circuitry 2008 is used to send and receive information over awireless link or network to one or more other devices and includeswell-known circuitry for performing this function. RF circuitry 2008 andaudio circuitry 2010 are coupled to processing system 2004 viaperipherals interface 2016. Interface 2016 includes various knowncomponents for establishing and maintaining communication betweenperipherals and processing system 2004. Audio circuitry 2010 is coupledto audio speaker 2050 and microphone 2052 and includes known circuitryfor processing voice signals received from interface 2016 to enable auser to communicate in real-time with other users. In some examples,audio circuitry 2010 includes a headphone jack (not shown).

Peripherals interface 2016 couples the input and output peripherals ofthe system to processor 2018 and computer-readable medium 2001. One ormore processors 2018 communicate with one or more computer-readablemediums 2001 via controller 2020. Computer-readable medium 2001 can beany device or medium that can store code and/or data for use by one ormore processors 2018. Medium 2001 can include a memory hierarchy,including but not limited to cache, main memory and secondary memory.The memory hierarchy can be implemented using any combination of RAM(e.g., SRAM, DRAM, DDRAM), ROM, FLASH, magnetic and/or optical storagedevices, such as disk drives, magnetic tape, CDs (compact disks) andDVDs (digital video discs). Medium 2001 may also include a transmissionmedium for carrying information-bearing signals indicative of computerinstructions or data (with or without a carrier wave upon which thesignals are modulated). For example, the transmission medium may includea communications network, including but not limited to the Internet(also referred to as the World Wide Web), intranet(s), Local AreaNetworks (LANs), Wide Local Area Networks (WLANs), Storage Area Networks(SANs), Metropolitan Area Networks (MAN) and the like.

One or more processors 2018 run various software components stored inmedium 2001 to perform various functions for system 2000. In someexamples, the software components include operating system 2022,communication module (or set of instructions) 2024, touch processingmodule (or set of instructions) 2026, graphics module (or set ofinstructions) 2028, and one or more applications (or set ofinstructions) 2030. Each of these modules and above noted applicationscorrespond to a set of instructions for performing one or more functionsdescribed above and the methods described in this application (e.g., thecomputer-implemented methods and other information processing methodsdescribed herein). These modules (i.e., sets of instructions) need notbe implemented as separate software programs, procedures or modules, andthus various subsets of these modules may be combined or otherwisere-arranged in various examples. In some examples, medium 2001 may storea subset of the modules and data structures identified above.Furthermore, medium 2001 may store additional modules and datastructures not described above.

Operating system 2022 includes various procedures, sets of instructions,software components and/or drivers for controlling and managing generalsystem tasks (e.g., memory management, storage device control, powermanagement, etc.) and facilitates communication between various hardwareand software components.

Communication module 2024 facilitates communication with other devicesover one or more external ports 2036 or via RF circuitry 2008 andincludes various software components for handling data received from RFcircuitry 2008 and/or external port 2036.

Graphics module 2028 includes various known software components forrendering, animating and displaying graphical objects on a displaysurface. In examples in which touch I/O device 2012 is a touch sensingdisplay (e.g., touch screen), graphics module 2028 includes componentsfor rendering, displaying, and animating objects on the touch sensingdisplay.

One or more applications 2030 can include any applications installed onsystem 2000, including without limitation, a browser, address book,contact list, email, instant messaging, word processing, keyboardemulation, widgets, JAVA-enabled applications, encryption, digitalrights management, voice recognition, voice replication, locationdetermination capability (such as that provided by the globalpositioning system (GPS)), a music player, etc.

Touch processing module 2026 includes various software components forperforming various tasks associated with touch I/O device 2012 includingbut not limited to receiving and processing touch input received fromI/O device 2012 via touch I/O device controller 2032.

I/O subsystem 2006 is coupled to touch I/O device 2012 and one or moreother I/O devices 2014 for controlling or performing various functions.Touch I/O device 2012 communicates with processing system 2004 via touchI/O device controller 2032, which includes various components forprocessing user touch input (e.g., scanning hardware). One or more otherinput controllers 2034 receives/sends electrical signals from/to otherI/O devices 2014. Other I/O devices 2014 may include physical buttons,dials, slider switches, sticks, keyboards, touch pads, additionaldisplay screens, or any combination thereof.

If embodied as a touch screen, touch I/O device 2012 displays visualoutput to the user in a GUI. The visual output may include text,graphics, video, and any combination thereof. Some or all of the visualoutput may correspond to user-interface objects. Touch I/O device 2012forms a touch sensing surface that accepts touch input from the user.Touch I/O device 2012 and touch screen controller 2032 (along with anyassociated modules and/or sets of instructions in medium 2001) detectsand tracks touches or near touches (and any movement or release of thetouch) on touch I/O device 2012 and converts the detected touch inputinto interaction with graphical objects, such as one or moreuser-interface objects. In the case in which device 2012 is embodied asa touch screen, the user can directly interact with graphical objectsthat are displayed on the touch screen. Alternatively, in the case inwhich device 2012 is embodied as a touch device other than a touchscreen (e.g., a touch pad), the user may indirectly interact withgraphical objects that are displayed on a separate display screenembodied as I/O device 2014.

Touch I/O device 2012 may be analogous to the multi-touch sensingsurface described in the following U.S. Pat. No. 6,323,846 (Westerman etal.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No.6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1,each of which is hereby incorporated by reference.

Examples in which touch I/O device 2012 is a touch screen, the touchscreen may use LCD (liquid crystal display) technology, LPD (lightemitting polymer display) technology, OLED (organic LED), or OEL(organic electro luminescence), although other display technologies maybe used in other examples.

Feedback may be provided by touch I/O device 2012 based on the user'stouch input as well as a state or states of what is being displayedand/or of the computing system. Feedback may be transmitted optically(e.g., light signal or displayed image), mechanically (e.g., hapticfeedback, touch feedback, force feedback, or the like), electrically(e.g., electrical stimulation), olfactory, acoustically (e.g., beep orthe like), or the like or any combination thereof and in a variable ornon-variable manner.

System 2000 also includes power system 2044 for powering the varioushardware components and may include a power management system, one ormore power sources, a recharging system, a power failure detectioncircuit, a power converter or inverter, a power status indicator and anyother components typically associated with the generation, managementand distribution of power in portable devices.

In some examples, peripherals interface 2016, one or more processors2018, and memory controller 2020 may be implemented on a single chip,such as processing system 2004. In some other examples, they may beimplemented on separate chips.

Examples of the disclosure can be advantageous in better recognizing andidentifying contact patches near an edge of a touch sensing surface,making use of an electronic device with a touch sensing surface moreintuitive and less frustrating to operate.

Although the disclosed examples have been fully described with referenceto the accompanying drawings, it is to be noted that various changes andmodifications will become apparent to those skilled in the art. Suchchanges and modifications are to be understood as being included withinthe scope of the disclosed examples as defined by the appended claims.

What is claimed is:
 1. A method of a computing device including a touchsensing surface, the method comprising: obtaining a proximity image fromthe touch sensing surface; segmenting the proximity image to identify atleast a first patch including one or more touch nodes in an edge columnof the proximity image; determining an edge centroid of the one or moretouch nodes of the first patch in the edge column; determining anadjacent centroid of one or more touch nodes of the first patch in anadjacent column, the adjacent column being adjacent to the edge column;copying the one or more touch nodes of the first patch in the edgecolumn to a border column in the proximity image, including offsettingthe copied touch nodes in the border column based on an extrapolation ofthe adjacent centroid and the edge centroid; and fitting an ellipse tothe first patch including the one or more touch nodes in the bordercolumn.
 2. The method of claim 1, wherein offsetting the copied touchnodes based on the extrapolation of the adjacent centroid and the edgecentroid includes subtracting the adjacent centroid from the bordercentroid to obtain a shift value and shifting the copied touch nodesbased on the shift value.
 3. The method of claim 2, wherein the shiftvalue is a non-integer value and shifting the copied touch nodes basedon the shift value includes interpolating the copied touch nodes in theborder column based on the shift value.
 4. The method of claim 1,further comprising: summing the one or more touch nodes of the firstpatch in the edge column to obtain an edge sum; summing the one or moretouch nodes of the first patch in the adjacent column to obtain anadjacent sum; and scaling the touch nodes in the border column based onan extrapolation of the edge sum and the adjacent sum.
 5. The method ofclaim 4, wherein the extrapolation of the edge sum and the adjacent sumincludes one of a linear extrapolation and a logistic extrapolation. 6.A method of a computing device including a touch sensing surface, themethod comprising: obtaining a major axis of a contact on or near thetouch sensing surface; obtaining a distance of the contact from an edgeof the touch sensing surface; based on a thumb profile, determining areference major axis of a thumb contact at the obtained distance; andidentifying the contact as a thumb based on the reference major axis andthe major axis of the contact.
 7. The method of claim 6, furthercomprising subtracting the reference major axis from the major axis ofthe contact to obtain an axis difference; wherein identifying thecontact as a thumb based on the reference major axis and the major axisof the contact includes identifying the contact as a thumb based on theaxis difference.
 8. The method of claim 7, further comprising adding theaxis difference to a sum of axis differences from previous time steps;wherein identifying the contact as a thumb based on the axis differenceincludes identifying the contact as a thumb based on the sum of axisdifferences.
 9. The method of claim 8, further comprising determiningthat the sum of axis differences is positive; wherein identifying thecontact as a thumb based on the sum of axis differences includesidentifying the contact as a thumb based on the determination that thesum of axis differences is positive.
 10. The method of claim 6, whereinthe contact is identified as a thumb after exceeding a time thresholdmeasured from the touchdown of the contact.
 11. The method of claim 6,wherein the contact is identified as a thumb after the contact hasreached a distance threshold from the edge of the touch sensing surface.12. A non-transitory computer readable medium, the computer readablemedium containing instructions that, when executed, perform a method ofa computing device including a touch sensing surface, the methodcomprising: obtaining a proximity image from the touch sensing surface;segmenting the proximity image to identify at least a first patchincluding one or more touch nodes in an edge column of the proximityimage; determining an edge centroid of the one or more touch nodes ofthe first patch in the edge column; determining an adjacent centroid ofone or more touch nodes of the first patch in an adjacent column, theadjacent column being adjacent to the edge column; copying the one ormore touch nodes of the first patch in the edge column to a bordercolumn in the proximity image, including offsetting the copied touchnodes in the border column based on an extrapolation of the adjacentcentroid and the edge centroid; and fitting an ellipse to the firstpatch including the one or more touch nodes in the border column. 13.The non-transitory computer readable medium of claim 12, whereinoffsetting the copied touch nodes based on the extrapolation of theadjacent centroid and the edge centroid includes subtracting theadjacent centroid from the border centroid to obtain a shift value andshifting the copied touch nodes based on the shift value.
 14. Thenon-transitory computer readable medium of claim 13, wherein the shiftvalue is a non-integer value and shifting the copied touch nodes basedon the shift value includes interpolating the copied touch nodes in theborder column based on the shift value.
 15. The non-transitory computerreadable medium of claim 12, the method further comprising: summing theone or more touch nodes of the first patch in the edge column to obtainan edge sum; summing the one or more touch nodes of the first patch inthe adjacent column to obtain an adjacent sum; and scaling the touchnodes in the border column based on an extrapolation of the edge sum andthe adjacent sum.
 16. The non-transitory computer readable medium ofclaim 15, wherein the extrapolation of the edge sum and the adjacent sumincludes one of a linear extrapolation and a logistic extrapolation. 17.A non-transitory computer readable medium, the computer readable mediumcontaining instructions that, when executed, perform a method of acomputing device including a touch sensing surface, the methodcomprising: obtaining a major axis of a contact on or near the touchsensing surface; obtaining a distance of the contact from an edge of thetouch sensing surface; based on a thumb profile, determining a referencemajor axis of a thumb contact at the obtained distance; and identifyingthe contact as a thumb based on the reference major axis and the majoraxis of the contact.
 18. The non-transitory computer readable medium ofclaim 17, the method further comprising subtracting the reference majoraxis from the major axis of the contact to obtain an axis difference;wherein identifying the contact as a thumb based on the reference majoraxis and the major axis of the contact includes identifying the contactas a thumb based on the axis difference.
 19. The non-transitory computerreadable medium of claim 18, the method further comprising adding theaxis difference to a sum of axis differences from previous time steps;wherein identifying the contact as a thumb based on the axis differenceincludes identifying the contact as a thumb based on the sum of axisdifferences.
 20. The non-transitory computer readable medium of claim19, the method further comprising determining that the sum of axisdifferences is positive; wherein identifying the contact as a thumbbased on the sum of axis differences includes identifying the contact asa thumb based on the determination that the sum of axis differences ispositive.
 21. The non-transitory computer readable medium of claim 17,wherein the contact is identified as a thumb after exceeding a timethreshold measured from the touchdown of the contact.
 22. Thenon-transitory computer readable medium of claim 17, wherein the contactis identified as a thumb after the contact has reached a distancethreshold from the edge of the touch sensing surface.
 23. An electronicdevice, comprising: a touch sensing surface; a processor to executeinstructions; and a memory coupled with the processor to storeinstructions, which when executed by the processor, cause the processorto perform operations to generate an application programming interface(API) that allows an API-calling component to perform a method of theelectronic device, the method comprising: obtaining a proximity imagefrom the touch sensing surface; segmenting the proximity image toidentify at least a first patch including one or more touch nodes in anedge column of the proximity image; determining an edge centroid of theone or more touch nodes of the first patch in the edge column;determining an adjacent centroid of one or more touch nodes of the firstpatch in an adjacent column, the adjacent column being adjacent to theedge column; copying the one or more touch nodes of the first patch inthe edge column to a border column in the proximity image, includingoffsetting the copied touch nodes in the border column based on anextrapolation of the adjacent centroid and the edge centroid; andfitting an ellipse to the first patch including the one or more touchnodes in the border column.
 24. The electronic device of claim 23,wherein offsetting the copied touch nodes based on the extrapolation ofthe adjacent centroid and the edge centroid includes subtracting theadjacent centroid from the border centroid to obtain a shift value andshifting the copied touch nodes based on the shift value.
 25. Theelectronic device of claim 24, wherein the shift value is a non-integervalue and shifting the copied touch nodes based on the shift valueincludes interpolating the copied touch nodes in the border column basedon the shift value.
 26. The electronic device of claim 23, the methodfurther comprising: summing the one or more touch nodes of the firstpatch in the edge column to obtain an edge sum; summing the one or moretouch nodes of the first patch in the adjacent column to obtain anadjacent sum; and scaling the touch nodes in the border column based onan extrapolation of the edge sum and the adjacent sum.
 27. Theelectronic device of claim 26, wherein the extrapolation of the edge sumand the adjacent sum includes one of a linear extrapolation and alogistic extrapolation.
 28. An electronic device, comprising: a touchsensing surface; a processor to execute instructions; and a memorycoupled with the processor to store instructions, which when executed bythe processor, cause the processor to perform operations to generate anapplication programming interface (API) that allows an API-callingcomponent to perform a method of the electronic device, the methodcomprising: obtaining a major axis of a contact on or near the touchsensing surface; obtaining a distance of the contact from an edge of thetouch sensing surface; based on a thumb profile, determining a referencemajor axis of a thumb contact at the obtained distance; and identifyingthe contact as a thumb based on the reference major axis and the majoraxis of the contact.
 29. The electronic device of claim 28, the methodfurther comprising subtracting the reference major axis from the majoraxis of the contact to obtain an axis difference; wherein identifyingthe contact as a thumb based on the reference major axis and the majoraxis of the contact includes identifying the contact as a thumb based onthe axis difference.
 30. The electronic device of claim 29, the methodfurther comprising adding the axis difference to a sum of axisdifferences from previous time steps; wherein identifying the contact asa thumb based on the axis difference includes identifying the contact asa thumb based on the sum of axis differences.
 31. The electronic deviceof claim 30, the method further comprising determining that the sum ofaxis differences is positive; wherein identifying the contact as a thumbbased on the sum of axis differences includes identifying the contact asa thumb based on the determination that the sum of axis differences ispositive.
 32. The electronic device of claim 28, wherein the contact isidentified as a thumb after exceeding a time threshold measured from thetouchdown of the contact.
 33. The electronic device of claim 28, whereinthe contact is identified as a thumb after the contact has reached adistance threshold from the edge of the touch sensing surface.